Ebosive-blast apparatus



F. G. GASCHE.

ERoslvE BLAST APPARATUS.

APPLICATION FILED 0CT.20, 1917.

Patented Sept. 30, IMQ.

FERDNAND Gr. GASCHE, 0F CHCAG, lLLINGS.

EROSIVE-BLAST APPARATUS.

Specification of Letters Patent.

Patented Sept 3GP, i919,

Application filed October v20, 1917. Serial No. 197,592.

To all wlw/n t may concern:

Be it known that l, FERDINAND G. GASCHE, a citizen of the United States, and a resident of Chicago, county ot' Cook,`a1id State of lllinois, have invented certain new and useful Improvements in Erosive-Blast Apparatus, of which the following is a specification.

My invention relates generally to improvements in erosive blast apparatus, of which the sand blast is an examp-le, and relates more particularly to improvements in that part of the apparatus that governs and controls the direction, character, and motion of the blast and its impingement upon and against the surfaces to betreated.

The general object ofvmy invention is to increase 'the eliiciency of erosive blast apparatus.

Further objects of my invention are to simplify the construction of' erosive blast apparatus; increase the durability thereof; and generally to improve the construction and operation thereof'. 'A

lpropose to increase enormouslyv the str1king force of the abrasive material by utilizu ing the potential energy of the air, steam, or other elastic medium commonly known as pressure energy through the use of expanding nozzles of' proper size and shape. llhc p-ressure energy still resident ina jet of steam or other elastic medium at the time of leaving the throat or narrowest part of the nozzle can be applied to producing a greater velocity of the elastic medium than that due to the pressure at the throat, provided the elastic medium is allowed to expand gradually in a conical or conical-like extension 0f the nozzle beyond the throat. The elastic medium may be thus confined until it has attained an outlet pressure of the atmosphere, if desired, and the velocity at the exit of such a. compound nozzle will be enormously increased over the exit velocity of a nozzle withoutvsuch an extension. lf such a compound nozzle is the' outlet for air at 140 pounds absolute pressure, l find that the exit velocity will be far in excess of 1000 feet per second and may even reach MOO per second.A Furthermore, l nd that the frictional resistance in nozzles having such outlets can be made so low that )ractically all of this velocity energy of the `)et is available for moving the particles ol sand or other abrasive material. ln other words, that tendency to lateral expansion of the jet issuing from all other crosivc blast apparatus` with which'll am familiar, is obviated b v a device embodying m invention as above generally set forth'. he jet also issues as nearly cylindrical with the consequent concentration of energy on a surface ot impingement and a resident energy of the abrasive material of a magnitude not heretofore available in the arts.

ln order to keep the Wear of internal surfaces of' pipes and fittings at a minimum, l cause the delivery of' the abrasive material through a conduit separate from that'carrying the working fluid up to the tip of a sand nozzle having an opening centrally and axially located with reference to the compound expanding nozzle. Furthermore, the tip of this sand nozzle is in the near vicinity of the throat of the expanding nozzle and causes the delivery of the particles of abrasive material in the central portion of the jet and near the region where a rapid change of ve' locity of the working fluid is imposed by the nozzle conditions. rllhe parallelism of the stream lilies ot' the fluid as passing through the compound nozzle precludes the possibility o't the impingement of the abrasive material on the walls ofl the nozzle and hence wear trom this cause will be very little.

My invention consists generally in the t'ormv` construction, arrangement, and coperation of parts whereby the above named objects, together with others which will appear hereinafter, are attained and my inven tion will bemore readily understood by reference to the accompanying drawing which illustrates that embodiment or" my invention which ll consider the best at the present time. rlllhe said drawing is a 'Vertical central view showing part. of the apparatus in section and part thereof in elevation, in order to disclose more clcarly the construction and coperation of the parts. A

lWhile the device shown inthe drawing is of a portable construction, my invention fully contemplates a construction directing energies of. suoli magnitude that a fixed or non-portable installation may be necessary. rll`he apparatus comprises generally a body portion, 1, a handle portion, 2, and an exit, outlet, or nozzle portion, 3. vThe nozzle 3 l shall refer to as a compound expansion nozzlc, inasmuch as it comprises an outlet portion, 4f, a smaller throat portion, 5, anda generally conical port-ion, 6, between the' portions -t and 5 thus forming a conically diverglng nozzle perror nog the expansion lill@ of the fluid and hence being an expansion nozzle. I refer to make the increase in size from tiie portion, 5, to the portion, 4, about one unit for ten units f length Where air is the Working Huid. 7 is an abruptly enlarged portion of the nozzle leading the air or steam under reservoir pressure to the orifice or throat 5, which is preferably provided With a rounded approach, 8, to minimize frictional losses. The nozzle chamber, 7, communicates immediately with the pressure chamber, 9, Within the body, l, of the apparatus. I prefer to make the nozzle part readily separable from the body to the end that it may be quickly and easily removed for examination and repair, and to this end I provide it with screw threads, 10, for coaction With screw threads, 11, of the body. I also prefer to provide a nut-like portion, 12, on the nozzle for convenience iny removingl and replacing; Leading from the chamber, 9, of the bodyA portion is an air supply opening, 13, leading .to the control valve, 14, and finally to the connection, 15, designed for the attachment of a hose, pipe, or other conduit connected to a suitable pressure apparatus. The air valve, 14, operates in a suitable chamber provided with a properly surfaced interior by means of a sleeve, 16, which is held in proper position b means of the opposed nuts, 17, and 1,8. 'Ille sleeve, 16, is provided with openings, 19, and 20 for coaction with the groove, 21,

of the valve, 14, when the lvalve is alined therewith. I prefer to make the valve, 14, close automatically and to this end I provide a spring, 22, normally pressin it upward .to the closed position indicat in the drawing. For the purpose ofv actuating the valve, I provide a stem, 23, connected to a link, 24, which in turn is secured to the trigger, 25, pivoted to the handle, 2, at 26. Thus when the hand embraces the handle, 2, it is ina position convenient to actuate the trigger, 25, by an upward pressure. The handle, 2, also contains a button, 27, reacting against a spring, 28, and through the medium of rod29, and pivoted lever, 30, serving to raise or lower the stem, 31, provided with the needle-valve end32. The

movement of the needle-valve obviously con.

trols the rate of efflux f the sand or other abrasive material through the opening, 32', of the sand nozzle, 33. The sand or other abrasive material is contained Within the member, 33, and is admitted there-to through attain a considerable velocity at the throat, 5, but reach their highest velocity at the outlet, 4, for the reasons heretofore described.

It Will be noted that the elastic fluid practically surrounds the stream of abrasive material as it passes through the throat and hence an abrading action on the compound nozzle is prevented. By using a suitable length expanding nozzle, the pressure of the Working fiuid will be so reduced as it reaches the outlet, 4, that the jet Will issue in substantially cylindrical form and with but little tendency to lateral expansion for a distance of'many inches. During all of the travel of the Working fiuid from the vicinity of the throat, 5, to the above distance remote from the nozzle, there is a continued acceleration of the particles of abrasive ma- ,terial Within the jet, and a tendency to attain the actual velocity of exit of the Working fluid.

While I have described 'a compound expanding nozzle with a conically divergent expansion chamber, the sections of said noz zle are not necessarily circular in order to realize the advantages of my invention. If particular or special applications of the erosive blast apparatus requires square, rectangular or other sections of nozzle, the underlying principle of conversion of pressure energy into velocity energy of the Working fluid can, by providing a controlled expansion of the elastic fluid, be applied.

It may be desirable to make the nozzle 3 of different lengths for Adifferent work. This may be accomplished practically by providing nozzle sections, one of Which is shown. by means of dotted lines in the drawings.

I claim:

l. In an erosive blast apparatus, a body portion formed with a pressure chamber for an elastic fluid; a compound nozzle having a a throat portion, an abruptly enlarged chamber leading from the throat portion and communicating with the pressure chamber, and a relatively long conical conduit leading away from the throat and pressurechamber; and an zabrasive material conduit terminating adjacent the throat of theV com pound -nozzle and adapted to discharge material into the conical conduit, as and for the purpose specified.

2. In an erosive blast apparatus, a body portion formed with a pressure chamber for an elastic fluid; a compound nozzle having a throat portion, an abruptly enlarged charnber leading from the throat portion and communicating with the pressure chamber, and a relatively long conical conduit leading away from the throat and V"pressure chamber; and an`abrasive material conduit terminating adacent the throat of said compound nozzle and having an opening positioned to discharge material centrally and 13o aangaan 3. ln an erosive blast apparatus, a body portion formed withI a pressure -chamber for an elastic duid, a compound nozzle having a throat portion, an abruptly enlarged chamber leading from the throat portion and communicating'with the pressure chamber, and a relatively long conical conduit leading away chamber; an abrasive material conduit terminating adjacent the throat of said oom- -pound nozzle and having and opening positioned to discharge material centrally and axially into the conical conduit;l and means for controlling the rate of emu): of material from said material conduit.

4. lin an 'erosiveblast apparatus, a body from the throat and pressureportion formed with a pressure chamber for an elastic Huid; a compound nozzle having a throat portion, an abruptly enlarged chamber leading from the throat portion and communicating with the pressure chamber; a relatively long conical conduit leading away from thepressure chamber; and an abrasive material conduit. terminating adjacent the throat of the compound nozzle and formed and adapted to discharge abrasive material under pressure into the conical conduit, so that upon its issuance from the abrasive material conduit it shall already have gained a certain initial velocity.

ln testimony whereof, l have hereunto set my hand this tthday of ctober, 1917.'

lFlE'RlDlIhTAND G., GASCHE 

